1. Field of the Invention
The present invention relates generally to valves and the like. More particularly, the present invention is directed towards a slide valve for selectively opening an evacuation hole defined in a side wall of a box-like container.
2. Brief Description of the Background Art
Box-like containers are known for storage and transport of various bulk substances, such as metal powders. These containers are usually made of common inexpensive materials including various cellulosic panels widely known as cardboard, fiberboard, particle board and the like, as well as polymeric or metal sheets. The bulk pack containers may be produced in a wide variety of useful shapes. Generally speaking, the methods of filling, storing and evacuating the container, and its torsional strength and rigidity depend upon both its shape and the material of which it is constructed.
Thus, the precise application to which the box is intended often determines its configuration and construction. For these reasons, bulk substance containers are often produced having round, or regular square, pentagonal or hexagonal cross-sections and therefore, are especially strong.
Previously, bulk powdered materials have been delivered to end users in sealed containers without precut openings. Thus, in order to empty the container to utilize the powders, operators first manually cut an opening in the bottom part of the container and bottom cover. Such procedures resulted in numerous accidents to the cutting operators, causing both expense and lost operator time. Additionally, since the bottom cover may be structural to the container, once its integrity is breached, the container may no longer be sufficiently strong to be handled. Moreover, powder losses will occur whenever the container is removed from the fixture at which it is being utilized. This method is therefore rather inconvenient, and also quite messy in that the relatively fluid powders often spill.
In the past, this problem has been addressed by the use of a bottom dumping container having an evacuation opening on the bottom. Such a container utilizes a common rotary disc valve. The rotary disc valve is similar to the arrangement commonly used in grated Italian cheese containers in that it utilizes a discharge port defined in the bottom cover of the container and a rotating disc. The disc, which is usually made of sheet metal, defines an aperture of substantially the same size as that in the container bottom. Since the rotating valve disc is placed inside the container, the weight of the material to be emptied forces the disc against the bottom of the container and seals the bulk material container against leakage. By rotating the disc about its center using a socket and lever until the discharge port and disc aperture are aligned, whereby the container may be emptied. Although rotary disc valved containers are useful, it has been found that they are not compatible with the majority of the bulk material transfer apparatus commonly found in North America. Additionally, even when suitable transfer apparatus is readily available, the rotary disc valved containers are still somewhat inconvenient to use since they can only be opened when placed atop special pallets which define apertures for allowing the socket and lever access to the center of the rotary disc. Thus, other bulk substance containers have been devised which can be utilized with the press feeder system commercially available from, for instance, R. Pettigrew Industries. As seen in FIGS. 3 and 4, such feeder systems include a tilting base and a discharge chute.
The press feeder is operated by placing a pallet with a bulk substance container on the (horizontal) tilting base. A discharge hole is then manually cut in the front side of the bulk substance container in a predetermined location. The pallet is thereafter slid forward until the discharge hole abuts the discharge chute. Of course, powder losses rapidly occur as powder quickly spills from the discharge hole and falls on the fixture and floor while the pallet is being slid up to the discharge chute. The hydraulic base is then tilted so that the bulk pack material flows from the container through the discharge chute. Although such an arrangement provides a container which does not leak during shipping, as noted, powder material still spills during the interval after the discharge hole is cut in the container wall before such discharge hole is made to abut against the discharge chute. Additionally, accidents still occur from the operators inadvertently cutting themselves. Moreover, the bulk substance container cannot be removed from the fixture in which it is installed without spilling additional powder until the container has been completely emptied.
Thus, it is clear that it would be helpful to provide an inexpensive valve arrangement for use with conventional bulk material handling equipment which does not result in the spillage of powder materials or provide the opportunity for operator accidents.